U.S. patent number 6,662,562 [Application Number 10/030,304] was granted by the patent office on 2003-12-16 for method and device for regulating the boost pressure of an internal combustion engine.
This patent grant is currently assigned to Robert Bosch GmbH. Invention is credited to Manfred Birk, Thomas Bleile, Gerhard Engel, Wolfgang Kraemer, Frank Meier, Peter Rupp.
United States Patent |
6,662,562 |
Engel , et al. |
December 16, 2003 |
Method and device for regulating the boost pressure of an internal
combustion engine
Abstract
The turbine of the exhaust gas turbocharger, which is located in
the exhaust gas channel of the internal combustion engine, has a
variable geometry. The regulation of the boost pressure is
performed via an adjustment of the turbine geometry. A very rapid
response of the boost pressure regulation to a variable load, with
an overshoot of the specified value, which would damage the
turbocharger, being avoided, is achieved by determining a
manipulated variable for the turbine geometry as a function of the
exhaust gas back pressure prevailing in the exhaust gas channel
upstream from the turbine.
Inventors: |
Engel; Gerhard (Stuttgart,
DE), Birk; Manfred (Oberriexingen, DE),
Meier; Frank (Kornwestheim, DE), Bleile; Thomas
(Stuttgart, DE), Rupp; Peter (Remseck, DE),
Kraemer; Wolfgang (Stuttgart, DE) |
Assignee: |
Robert Bosch GmbH (Stuttgart,
DE)
|
Family
ID: |
7633772 |
Appl.
No.: |
10/030,304 |
Filed: |
May 10, 2002 |
PCT
Filed: |
February 16, 2001 |
PCT No.: |
PCT/DE01/00586 |
PCT
Pub. No.: |
WO01/66921 |
PCT
Pub. Date: |
September 13, 2001 |
Foreign Application Priority Data
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Mar 7, 2000 [DE] |
|
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100 10 978 |
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Current U.S.
Class: |
60/602 |
Current CPC
Class: |
F02D
37/02 (20130101); F02D 21/08 (20130101); F02B
37/24 (20130101); F02D 41/0007 (20130101); F02M
26/05 (20160201); F02D 2200/0402 (20130101); Y02T
10/12 (20130101); F02D 41/187 (20130101); F02D
2041/1419 (20130101); F02D 2200/0404 (20130101); F02D
2041/0017 (20130101); F02M 26/10 (20160201) |
Current International
Class: |
F02D
37/02 (20060101); F02D 41/00 (20060101); F02D
37/00 (20060101); F02D 21/00 (20060101); F02D
21/08 (20060101); F02B 37/24 (20060101); F02B
37/12 (20060101); F02M 25/07 (20060101); F02D
023/00 () |
Field of
Search: |
;60/600-603 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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37 31 320 |
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Apr 1988 |
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DE |
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41 07 693 |
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Sep 1992 |
|
DE |
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43 12 077 |
|
Jan 1994 |
|
DE |
|
198 08 832 |
|
Sep 1999 |
|
DE |
|
0 454 943 |
|
Nov 1991 |
|
EP |
|
Primary Examiner: Denion; Thomas
Assistant Examiner: Trieu; Thai-Ba
Attorney, Agent or Firm: Kenyon & Kenyon
Claims
What is claimed is:
1. A method for regulating a boost pressure of an internal
combustion engine including an exhaust gas turbocharger, the
turbocharger including a turbine located in an exhaust gas channel
of the internal combustion engine, the turbine including an
adjustable geometry, the method comprising: performing a regulation
of the boost pressure via an adjustment of the adjustable geometry
of the turbine; determining a manipulated variable for the
adjustable geometry of the turbine as a function of an exhaust gas
back pressure prevailing in the exhaust gas channel upstream from
the turbine; causing a first controller to establish a specified
exhaust gas back pressure from a deviation between a specified
boost pressure and an actual boost pressure; and causing a second
controller to derive the manipulated variable from a deviation
between the specified exhaust gas back pressure and one of a
measured actual exhaust gas back pressure and an estimated actual
exhaust gas back pressure.
2. The method according to claim 1, further comprising: measuring
an air mass flow intake via an air mass flow sensor disposed in the
intake manifold; and acting on the adjustable turbine geometry via
an actuator disposed next to the turbine.
3. A device for regulating a boost pressure of an internal
combustion engine including an exhaust gas turbocharger, the
turbocharger including a turbine located in an exhaust gas channel
of the internal combustion engine, the turbine including an
adjustable geometry, comprising: an arrangement for performing a
regulation of the boost pressure via an adjustment of the
adjustable geometry of the turbine; and a first controller for
producing a manipulated variable for the adjustable geometry of the
turbine as a function of an exhaust gas back pressure prevailing in
the exhaust gas channel upstream from the turbine; and a second
controller for determining a specified exhaust gas back pressure
from a deviation between a specified boost pressure and an actual
boost pressure; wherein the first controller derives the
manipulated variable from a deviation between the specified exhaust
gas back pressure and one of a measured actual exhaust gas back
pressure and an estimated actual exhaust gas back pressure.
4. The device according to claim 3, further comprising: an air flow
sensor to determine an air mass flow intake in the intake manifold;
and an actuator which acts on the adjustable turbine geometry
disposed next to the turbine.
Description
FIELD OF THE INVENTION
The present invention relates to a method and a device for
regulating the boost pressure of an internal combustion engine
having an exhaust gas turbocharger whose turbine, which is located
in the exhaust gas channel of the internal combustion engine, has
an adjustable geometry, with the regulation of the boost pressure
occurring via an adjustment of the turbine geometry.
BACKGROUND INFORMATION
As it is provided in, for example, German Published Patent
Application No. 41 07 693 or European Published Patent Application
No. 04 54 943, boost pressure regulation is typically performed by
a controller producing a manipulated variable as a function of the
deviation between a specified boost pressure and an actual boost
pressure. This manipulated variable is used either for controlling
a valve in a bypass which bypasses the turbine of the turbocharger
in the exhaust gas channel (see German Published Patent Application
No. 41 07 693) or for controlling the adjustable turbine guide
vanes of a turbine having variable geometry (see European Published
Patent Application No. 04 54 943).
Increasingly higher requirements are placed on, engines in regard
to exhaust gas and consumption characteristics. An exhaust gas
turbocharger having variable turbine geometry allows an adjustment
to the current engine operating point through adjustment of the
turbine guide vanes. With this technique, a delayed response of the
exhaust gas turbocharger (turbo lag) can be reduced and the
efficiency of the engine can be improved at the same time.
Overshoots of the boost pressure, which mechanically stress the
turbocharger very strongly, often occur during acceleration
operations. In addition, excessive closing of the variable turbine
geometry in the acceleration phase can result in an unwanted high
exhaust gas back pressure, which negatively influences the dynamic
response and efficiency of the engine.
SUMMARY OF THE INVENTION
The present invention therefore has as its object the provision of
a method and a device for boost pressure regulation of the type
cited initially which ensure that the boost pressure follows the
course of the desired boost pressure specified value as rapidly as
possible in the case of an alternating load, with an overshoot of
the boost pressure specified value being avoided to protect the
exhaust gas turbocharger from unnecessarily high loads.
The object cited is achieved in that a manipulated variable for the
turbine geometry is determined as a function of the exhaust gas
back pressure prevailing in the exhaust gas channel upstream from
the turbine. The exhaust gas back pressure responds significantly
faster than the boost pressure to changed behavior of the
controlled system--e.g., speed change, alternating load, change in
exhaust gas recirculation--or to malfunctions, e.g., in the
servo-system. Therefore, if the exhaust gas back pressure is used
according to the present invention to derive a manipulated
variable, a very rapid response of the boost pressure regulation to
a change in the preset specified boost pressure is achieved.
An advantageous refinement of the method according to the present
invention and the device according to the present invention is that
a specified exhaust gas back pressure is determined by a first
controller from the deviation between a specified boost pressure
and an actual boost pressure, and the manipulated variable for the
turbine geometry is derived by a second controller from the
deviation between the specified exhaust gas back pressure and a
measured or estimated actual exhaust gas back pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic view of an internal combustion engine
having an exhaust gas turbocharger.
FIG. 2 shows a flowchart for the regulation of the boost
pressure.
DETAILED DESCRIPTION
FIG. 1 shows an internal combustion engine 1 having an intake
channel 2 and an exhaust gas channel 3. Turbine 4 is located in
exhaust gas channel 3 and compressor 5 of an exhaust gas
turbocharger is located in intake channel 2. Furthermore, the
internal combustion engine can be equipped with an exhaust gas
recirculation channel 6 which connects exhaust gas channel 3 with
intake manifold 2. A controllable valve 7 is located in exhaust gas
recirculation channel 6. A pressure sensor 8 for measuring boost
pressure pld and an air mass flow sensor 9 for measuring air mass
flow intake lm are located in intake manifold 2. In addition, there
is a butterfly valve 10 in the intake manifold. A sensor 11 detects
the speed nmot of the internal combustion engine, and a pressure
sensor 12 in exhaust gas channel 3 measures exhaust gas back
pressure pag upstream from turbine 4. An actuator 13 is present
which acts on the turbine geometry, i.e., performs an adjustment of
the turbine guide vanes. This actuator 13 receives a manipulated
variable vtg from a controller 14. Controller 14 uses motor speed
nmot, butterfly valve position dk, airflow intake lm, boost
pressure pld, and exhaust gas back pressure pag as the input
variables to derive manipulated variable vtg for the turbine
geometry and a manipulated variable arf for the exhaust gas
recirculation valve.
The procedure that controller 14 uses for deriving manipulated
variable vtg for the turbine geometry from the input variables
cited will be described in more detail with reference to the
flowchart in FIG. 2. A processor PZ determines a specified boost
pressure plds from motor speed nmot, butterfly valve setting dk,
which reflects the intent of the driver, and possibly other
operating quantities of the engine not mentioned here. The
derivation of specified boost pressure plds will not be discussed
in more detail here, because it is part of the related art.
Deviation .DELTA.pld between specified boost pressure plds and an
actual boost pressure pld is determined in a first node V1.
Deviation value .DELTA.pld for the boost pressure is supplied to a
first controller R1 (e.g., PI or PID controller). The output
quantity of first controller R1 corresponds to a specified value
pags of the exhaust gas back pressure in exhaust gas channel 3.
Deviation .DELTA.pag between specified exhaust gas back pressure
pags and actual exhaust gas back pressure pag is established in a
second node V2. Deviation value .DELTA.pag for the exhaust gas back
pressure is supplied to a second controller R2, which finally
produces manipulated variable vtg for the variable turbine
geometry.
Actual boost pressure pld can either be measured by way of pressure
sensor 8 in intake manifold 2, or an estimate for the actual boost
pressure can be derived by processor PZ from various operating
quantities of the internal combustion engine. The dot-dash line in
FIG. 2 indicates that actual boost pressure pld is an estimate
determined by processor PZ. Actual exhaust gas back pressure pag
can be a measured value of pressure sensor 12 in exhaust gas
channel 3. However, actual exhaust gas back pressure pag can also
be an estimate derived by processor PZ from operating quantities of
the internal combustion engine. The dot-dash line leading from
processor PZ to second node V2 indicates that actual exhaust gas
back pressure pag is an estimate calculated by processor PZ. The
calculation of the estimates for actual boost pressure pld and
actual exhaust gas back pressure pag will not be discussed in more
detail here, because methods known from the related art can be used
in this case.
Exhaust gas back pressure pag in exhaust gas channel 3 upstream
from turbine 4, and thus also the energy injected into turbine 4,
increase through closing of the turbine geometry. For this reason,
the turbocharger speed and, at the same time, boost pressure pld in
intake manifold 2 increase. If there is exhaust recirculation, as
shown in FIG. 1, exhaust gas can reach the intake manifold via
exhaust gas recirculation channel 6 by opening valve 7, if exhaust
gas back pressure pag is greater than boost pressure pld. If
exhaust gas recirculation valve 7 is opened, exhaust gas back
pressure pag, and therefore also boost pressure pld in intake
manifold 2, drop.
The present invention is based on the observation that exhaust gas
back pressure pag responds significantly faster to an adjustment of
the turbine geometry than boost pressure pld. Boost pressure pld
responds only with a delay equal to the time constant of the
exhaust gas turbocharger. Therefore, the dynamic response of a
controller for the boost pressure is essentially limited by the
moment of inertia of the exhaust gas turbocharger. The time
constant occurring in this case is, however, significantly larger
than the time constant of several disturbances which act on the
system through the time-variant behavior of the controlled system,
through opening and closing of exhaust gas recirculation valve 7,
or through errors in the guide vane system of turbine 4.
Disturbances of the guide vane system of the turbine, changes in
the valve lift of exhaust gas recirculation valve 7, or changes in
the operating point of the internal combustion engine affect
exhaust gas back pressure pag very directly and can therefore be
compensated for very rapidly in the lower-level control loop having
controller R2. The upper-level control loop having controller R1 is
designed as slower than the lower-level control loop having
controller R2. However, since boost pressure pld is more sluggish
than exhaust gas back pressure pag anyway, this condition is
fulfilled automatically.
* * * * *